<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

</body>
<script>
    // let a = 1;
    // function foo() {
    //     console.log(a++); 
    //     // console.log(a)
    // }
    // foo() //1    2
    // foo() //2    3
    // foo() //3    4

    function foo(){
        let a = 1;
        a++;
        console.log(a)
    }
    foo() //2
    foo() //2
    foo() //2





</script>

</html>